Critically ill patients in a hospital are often supported by a mechanical ventilator that assists them in their breathing. The ventilator provides pressurized air that is coordinated with a patient's natural breathing to help ensure that they obtain sufficient oxygen for normal metabolic activity.
Such support can be a cornerstone for treatment of problems such as acute lung injury (ALI), and in its more severe form, acute respiratory distress syndrome (ARDS). ALI is caused by problems such as sepsis, pneumonia, and other maladies. ALI is present, on average, in seven percent of ICU admissions and carries an in-hospital mortality rate of 40-50 percent. ALI is generally treated by keeping the PaO2>60 mmHg, without causing injury to the lungs with excessive O2 or volutrauma. Improperly-provided ventilation may result in ventilator-induced lung injury (VILI). Proper individualized settings for ventilator support may thus be important to prevent the ventilator itself from further damaging a patient's lung or lungs. However, caregivers frequently fail to recognize ALI/ARDS in patients who have it.